Combustor heat shields provide protection to the combustor shell. Combustor dome heat shields may be provided with radially inner and outer lips. These lips are exposed to high gas temperature relative to the remainder of an otherwise well-cooled heat shield, resulting in hot spots with high thermal gradients. The thermal gradient inevitably results in cracks due to thermal mechanical fatigue. Cracking in the lips further deteriorates cooling effectiveness and results in additional damage due to high temperature oxidation. The front heat shields mounted to the combustor shells adjacent to the dome heat shields have leading edge portions adjacent to the lips of the dome heat shields that may be starved from cooling air and develop hot spots as well.
Accordingly, there is a need for an improved cooling scheme while avoiding any detrimental effect on the rest of the heat shield surface cooling.